Method of fabricating frozen fine liver piece for artificial liver, apparatus for freezing the same and freezing vessel

ABSTRACT

A method of fabricating frozen fine liver pieces for an artificial liver which comprises cutting a liver removed from a human being or an animal, from which blood is removed into fine pieces of square shape and freezing the liver pieces with helium gas. A freezing apparatus for an artificial liver which has gas phase pressurizing means for pressurizing liquid helium coupled to a chamber for storing the liquid helium, a helium gas conduit dipped in the liquid helium passed through the chamber to be closed and contained, in which the liver fine pieces are telescopically received and an exhaust conduit provided with a control valve coupled to the freezing chamber. And, a freezing vessel for an artificial liver which has a flow conduit capable of being coupled to an upper portion and a lower portion of a unit, an upper coupling port and a lower coupling port respectively formed therethrough with closing plugs, two or more mesh plates laterally laid elevationally in the unit, and exit opening in to a containing chamber thus formed.

This is a divisional of application Ser. No. 245,925 filed Sept. 16,1988, now U.S. Pat. No. 4,883,452, which is a continuation applicationof Ser. No. 661,469, filed Oct. 16, 1984, abandoned.

BACKGROUND OF THE INVENTION

This invention relates to an artificial liver adapted for an artificialliver supplementing apparatus used for subsidizing the function of theliver of a patient who has a liver disease such as a severe hepatitisand, more particularly, to a method of fabricating frozen fine liverpieces capable of preserving the frozen liver, an apparatus for freezingto execute the same method, and a freezing vessel for fabricating thesame.

There is, heretofore, a biological artificial liver which utilizes theliving liver of an animal (a dog) retained in a living body as theabove-described artificial liver, but such a liver should be provided inthe vicinity of a patient (the dog). A dialysis of blood has alreadybeen carried out with a cellophane membrane, a PAN membrane, a cationexchange resin, an activated charcoal, an albumin or a hydron as anonbiological artificial liver, but such dialysis can only supplementthe latter of the metabolic function and the detoxicating function ofthe liver, thereby resulting in unsatisfaction in the results of thetherapy.

Therefore, it has been tried to employ an artificial liver used from aliving liver excised externally from an animal. However, when the liverof a dog or a pig is used in this manner, the immunological differencebetween the liver of the dog or pig and a human being is desirable. Alarge result cannot be expected in this case. The liver of a baboon hasless such problems, but the probability of obtaining the liver of thebaboon is difficult.

It is heretofore known that the liver has its function even in the statethat the liver loses its normal state as an organ and finely dividedinto tissues or individual cells. From this standpoint, the human oranimal's livers of sliced state are already used as artificial liver.

In this case, it is required that the artificial liver can endureagainst the preservation for a long period of time and can be thawed andused as required.

To this end, the above-described artificial liver is frozen for thepreservation, but this method includes removing blood, slicing theexcised liver in the millimeter order of thickness, and freezing thesliced livers with liquid nitrogen. When the artificial livers thusobtained are thawed and used for the artificial auxiliary liver device,its urea producing function and glucose producing function as the liverof the artificial livers are extremely smaller than the case that freshliver is used, finished in a short time, and cannot be expected forsufficient practical effects.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method of freezing aliver, which can eliminate the aforementioned drawbacks anddisadvantages, can endure against the preservation for a long period oftime and can sufficiently exhibit the functions of the liver at thethawed and used time, and advantageously has cutting a liver removedfrom a human being or an animal, from which blood has been removed, intofine pieces of square shape an freezing the liver pieces with heliumgas.

Another object of the present invention is to provide an apparatus forfreezing a liver piece, which can uniformly, rapidly and instantaneouslyinject helium gas to the entire liver pieces in case of executing theaforementioned method, thereby efficiently and regularly freeze theliver piece at the moment to obtain a frozen liver piece capable ofexhibiting preferable liver functions at the thawing time.

Still another object of the present invention is to provide a freezingvessel capable of being used to freeze by the aforementioned method.

More particularly, the freezing vessel of the invention contemplates toeliminate the difficulties of inconvenience that a mere vessel cannotobtain a desirable result in the instantaneous freezing requiredparticularly for the liver pieces, the quantity of liver piecescontained once in the vessel is limited, cannot be largely increased ordecreased, cannot preserve the frozen liver nor be useful for the useafter thawing time and another implement must be employed.

The above and other related objects and features of the invention willbe apparent from a reading of the following description of thedisclosure found in the accompanying drawings and the novelty thereofpointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory longitudinal sectional front view of anembodiment of an apparatus used for thawing an artificial liver obtainedby an embodiment of a method of the invention and for measuring theliver functions;

FIGS. 2 and 3 are graphs respectively illustrating the measured resultsof urea producing function and glucose producing function obtained bythe measuring apparatus;

FIGS. 4(a) and 4(b) are explanatory perspective views showing artificiallivers according to prior art and the present invention;

FIG. 5 is an explanatory view showing an example of an artificialauxiliary liver device employing artificial liver;

FIG. 6 is a plan view of an essential section of a freezing apparatusaccording to a second embodiment of the present invention;

FIG. 7 is a front view partly cut out of the apparatus;

FIGS. 8 and 9 show different vessels used for the apparatus, wherein (a)'s illustrate exploded perspective views and (b) 's illustrate assembledperspective views;

FIG. 10 is a front view of a freezing vessel according to a thirdembodiment of the invention;

FIG. 11 is a longitudinal sectional front view of the vessel;

FIG. 12 is a longitudinal sectional front view of the vessel in anotherused state;

FIG. 13 is a front view of the freezing vessel according to a fourthembodiment of the invention;

FIG. 14 is a front longitudinal sectional view of the vessel;

FIG. 15 is a front longitudinal sectional view showing the other usedstate of the vessel; and

FIG. 16 is a front longitudinal sectional view showing the upper portionof the vessel of different embodiment of the invention from FIGS. 13-15.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A method of freezing a liver piece according to the present inventionwill be described in detail by a first embodiment using a dog withreference to the accompanying drawings. An abdomen is incised in anormal size, the portal vein of the liver is exposed, approx. 1000 ml.of heparin-added Ringer's lactate solution of 4° C. is flowed through atube internally engaged with the vein, the vena cava in the upper partof the liver is then excised, and the liver is excised.

Then, the liver is dipped in electrolyte out of cells equivalent to theabove Ringer's lactate solution simultaneously when the liver isexcised, and the liver is then removed from the solution. Preferably,the liver is cut to squares having approx. 3 to 5 mm per side in thesolution without removing from the solution, thereby producing a numberof liver fine pieces.

The liver fine pieces are frozen not by liquid nitrogen nor liquidhelium but by helium gas. The freezing means may include variousmechanisms such as, for example, placing the liver fine pieces in apredetermined closed cavity, and injecting helium gas evaporated fromliquid helium to the liver fine pieces in the closed cavity preferablyat a considerably high speed.

Thus, the liver fine pieces are instantaneously frozen, and the frozenliver fine pieces thus provided are dipped in low temperature liquefiedgas such as liquid nitrogen prepared separately for preservation.

In order to measure the function of the liver as the thawed artificialliver for the frozen liver fine pieces preserved as described above, aflask 2 containing 100 m. of 5%-fructose phosphoric acid buffer solutionis introduced into a constant-temperature oven 4 for storing hot water 3of 38° C. as shown in FIG. 1, 30 g. of frozen liver fine pieces 5 frozenby 100 m. of helium gas are filled in the buffer solution 1, 0.1 mg. ofammonium chloride per 1 g. of the liver is filled as a load, and oxygengas O₂ is applied into the solution in the flask 2 through a gas feedconduit 6.

The measured results of the urea nitrogen and glucose are respectivelyshown in FIGS. 2 and 3. Solid lines show the curves of the measuredresults of the frozen liver fine pieces obtained by the method accordingto the present invention, and broken lines show the curves of themeasured results of the conventional frozen liver fine pieces A slicedfrom the liver into thin pieces as shown in FIG. 4(a) and frozen by LN₂.

When the urea production ability of the liver shown in FIG. 2 is firstobserved, remarkable ability is exhibited as compared with the case ofthe conventional frozen liver fine pieces A, the liver acts sufficientlythe urea production ability up to 12 hours after the thawing (i.e., 2mg./g. liver/12 hours in average), and this exhibited that this resultis considerably near 4.1 mg./g. liver/24 hours of the urea productionability of the sliced fresh liver having 1 mm of thickness.

Further, as to the glucose production ability shown in FIG. 3, muchpreferable result is obtained as compared with the conventional examplein the same manner as the urea production ability, the livercontinuously acts sufficiently the glucose production ability to 12hours after the thawing, and could be confirmed to produce 17 mg./g.liver/12 hours.

The reasons why the frozen artificial liver provided according to thepresent invention results in excellent auxiliary liver functions asdescribed above are because the liver is not merely sliced into largethin pieces as in FIG. 4 (a) by the conventional method, but the liveris finely cut into cubes, rectangular prisms or triangular pyramidsshown in FIG. 4(b). Thus, only the outer periphery A' of theconventional liver in FIG. 4(a) serves to perform the liver functions,but the central portion A' which occupies the considerably proportion ofthe entirety shown by the hatched lines does not participate in theliver functions. On the other hand, slight corners of the centralportion 5' of the square liver fine pieces of the present invention donot serve to perform the liver functions as shown in FIG. 4(b), and whenthe blood flow is executed by the artificial auxiliary liver device, thecontacting area with the blood of the liver of the inventionadvantageously increases.

An example of the artificial auxiliary liver device is shown in FIG. 5.As shown in FIG. 5, the auxiliary liver device is used in parallel withthe artery of a patient B. Reference numerals 7 and 8 designate pumps.All blood C is separated into blood-plasma D and blood corpusclecomponent E by a blood-plasma separator 9. After the blood-plasma Dpasses the thawed artificial liver contained in a column 10, theblood-plasma D is returned together with the blood corpuscle componentto a human body through an artificial dialyzer 11 in this example.

Factors that the liver of the present invention results in excellentfunctions are points that square liver fine pieces are frozen, and notliquid helium but helium gas is employed using neither liquid nitrogennor nitrogen gas.

More particularly, the helium gas is considerably low temperature suchas -260° C., has 5.23 (kJ/kg.K) of specific heat, which is approx. fivetimes the nitrogen gas, with the result that it is considered that theliver can be frozen without destroying the tissue of the liver byutilizing the fact that the freezing velocity is very large such as1,000° C./min.

According to the present invention as exemplified in the firstembodiment, the liver is cut into square fine pieces, and the squareliver fine pieces are frozen by the helium gas. Therefore, the liver canretain sufficiently the same liver functions as the fresh liver to 12hours after the thawing. Further, since the liver is cut into squarefine pieces, the liver fine pieces can be not only readily frozen, butalso serve to readily and rapidly perform the liver functions even afterthe thawing. In addition, since the liver can be easily handled ascompared with the conventional sliced large thin pieces, the liver isconvenient in the constitution of the artificial auxiliary liver device,and can be preserved permanently with refrigerant such as liquidnitrogen.

An apparatus for freezing a liver as a second embodiment of the presentinvention will now be described in detail with reference to FIGS. 6 and7. In FIGS. 6 and 7, a chamber 21 for storing liquid helium 20 and afreezing chamber 22 disposed above the chamber 21 are provided so that alower end port is dipped in the liquid helium 20 through the chamber 21,and coupled via a helium gas conduit 24 passed through the bottom plate23 of the freezing chamber 22 at the upper end port.

Gas phase pressurizing means 26 such as a compressor is coupled from anupper port 21' through a pressurizing conduit 25 to the chamber 21, andthe internal pressure of the gas phase unit A of the chamber 2 can beaccordingly raised by operating the pressurizing means 26.

Then, the freezing chamber 22 can be closed by a cover 28 with a packing27, a control valve 30 is interposed at an exhaust conduit 29 coupled tothe upper peripheral side, and an adiabatic insulator 31 is sheathed onthe freezing chamber 22 and the helium gas conduit 24 as will bedescribed in more detail.

More specifically, a flange 33' of an adiabatic outer tank 33 is mountedon a flange 32 projected from the peripheral side of the freezingchamber 22, the helium gas conduit 24 is movably engaged with an outertank conduit 34 fastened to the bottom opening of the tank 33, and thelower end of the conduit 34 is sealingly fastened to the helium gasconduit 24, thereby forming an adiabatic gap or chamber 35 around thefreezing chamber 22 and the outer peripheral side of the conduit 24exposed with the outer atmosphere. Then, a vacuum pump 38 is providedthrough a vacuum evacuating conduit 37 provided with a control valve 36at the outer tank 33, thereby exhausting gas in the gap 35.

Further, in the embodiment exemplified in FIGS. 6 and 7, an opening 21"provided at the upper port 21' of the chamber 21 and a bottom plate ofthe tank 33 are coupled via a conduit 39 sheathed on the conduit 34,thereby communicating between a gap 40 between the conduit 39 and theconduit 34 and the gas phase unit A of the chamber 21, and a pressuregauge 41 for measuring the internal pressure of the gas phase unit A iscoupled to the conduit 39.

To employ the freezing apparatus thus constructed, liver fine pieces a,a, . . thus finely divided are contained in the freezing chamber 22, andthe chamber 22 is closed. In this case, the cover 28 with a packing 29is used to close the freezing chamber 22. To fasten the cover 28, thecover 28 is clamped by a clamping chain 42 to the freezing chamber 22 asshown in FIGS. 6 and 7. Prior to this clamping, a hanger 45 of afreezing vessel 44 is engaged with a vertical hook rod 43 from anadiabatic insulator B fastened to the cover 28, the vessel 44 iscontained in the freezing chamber 22, and the vessel 44 is placed onplacing stable arm bases provided in predetermined number at a conicalsupport 46 fastened to the bottom plate 23 of the freezing chamber 22.

The vessel 44 may employ various types, and examples of the vessel 44are shown in FIGS. 8 and 9.

In FIG. 8, a middle mesh bottom 49 is extended on a main cylinder 48provided with the hanger 45, a main tray 51 is formed by protruding asmall integral cylinder 50 of small diameter from the cylinder 48downwardly, and a threaded part 52 is formed on the outer peripheralwall of the cylinder 50 in the example exemplified in FIG. 8.

Further, as apparent in FIG. 8(a), integral trays 53, 53, . . . ofdesired number are prepared. The tray 53 is provided integrally with alarge-diameter portion 54 and a small-diameter portion 55. The threadedpart 52 of the tray 51 is engaged with the threaded part 54' formed onthe inner peripheral surface of the large-diameter portion 54, and thethreaded parts 55' formed on the outer periphery of the small-diameterportions 55 of the trays 53, 53, . . . of required number aresequentially engaged with the threaded part 54' of the large-diameterportion 53 of next stage, thereby associating the vessels 44 in a mannercapable of being disassembled as shown in FIG. 8(a). Then, middle meshbottoms 56 are respectively extended also on the trays 53, 53, . . . andliver fine pieces a, a, . . . to be frozen are placed on the middlebottom 56 and the middle mesh bottom 49 of the tray 51 therein.

Next, the freezing vessel 44 exemplified in FIG. 9 will be described indetail. A mesh bottom board 58 is extended on the bottom of a vesselbody 57 shown in FIG. 9(a), and the liver fine pieces a, a, . . . arecontained in the vessel body. Threaded parts 59 and 60 are respectivelyformed on the upper and lower outer peripheries of the body 57, an uppercover 61 formed with the hanger 45 is engaged with the threaded part 59,and a lower cover 62 is engaged with the threaded part 60. Thus, thefreezing vessel 44 shown in FIG. 9(b) is constructed. An outflowcylinder 63 and an inflow cylinder 64 are respectively protrudedlongitudinally from the centers of the upper and lower covers 61 and 62to pass helium gas to the vessel 44 as will be described in detail.

As described above, the freezing vessel 44 which has readily containedliver fine pieces a, a,. . . cut in square of several mm in side ismounted in the freezing chamber 22, the chamber 22 is closed by thecover 28 as described above, the pressurizing means 26 is operated toraise the internal pressure of the chamber 21 to a predeterminedpressure (e.g., approx. 600 mmAg), and the pressure is confirmed by thepressure gauge 41.

In this case, the vacuum pump 38 is naturally operated in advance, toevacuate the gap 35 in vacuum state, thereby enabling to sufficientlyperform the adiabatic effect.

When the internal pressure of the chamber 21 is raised to apredetermined pressure as described above, the control valve 30 providedin the conduit 29 is manually or automatically opened, and the conduit29 is opened with the outer atmosphere.

Thus, helium is gasified from the surface of the liquid helium in theconduit 24, and raised. After the freezing chamber 22 is filled with thehelium gas, the helium gas is exhausted from the conduit 29 thus openedinto the atmosphere. Then, the liver fine pieces a, a, . . . containedin the freezing chamber 22 are instantaneously frozen in contact withthe helium gas in this case.

As exemplified by the above-described second embodiment of the apparatusof the invention, the gas phase pressurizing means 26 for pressurizingthe liquid helium 20 is coupled to the chamber 21 for storing the liquidhelium 20, the helium gas conduit 24 dipped in the liquid helium 20 ispassed through the chamber 21 to allow the conduit 24 to communicatewith the freezing chamber 22 to be closed and contained, in which theliver fine pieces a, a, . . . are telescopically received, and theexhaust conduit 29 provided with the control valve 30 is coupled to thefreezing chamber 22. Therefore, the helium gas abruptly gasified fromthe liquid helium and incoming to the freezing chamber 22 for containingthe liver fine pieces a, a, . . . is supplied to and passed through thefreezing chamber 22. Thus, the helium gas can be rapidly and uniformlycontacted with the liver fine pieces contained in the freezing chamber22. Therefore, the liver fine pieces can be uniformly frozeninstantaneously at the helium temperature, and are frozen with necessaryand sufficient consumption amount of the helium gas. Consequently, afreezing apparatus which has no waste of helium gas can be provided.

A third embodiment as a freezing vessel used to execute the method ofthe first embodiment of the invention will now be described in detailwith reference to FIGS. 10 to 12. The vessel is slightly similar to thatin FIG. 9, but this vessel is composed at least of a cover unit 70 and abottom unit 71, as well as one or more of coupling cylinder units 72,72, . . associated between the cover unit 70 and the bottom unit 71,which may be preferably formed of members made of synthetic resin suchas Teflon.

The cover unit 70 is of an essentially solid, unperforated constructionbeing formed of a ceiling plate 73, and a peripheral side wall 74 in atray shape, an upper coupling port 75 is passed at the center of theceiling plate 73, and the port 75 is closed by a mesh plate 76 bonded tothe inner surface of the ceiling plate 73.

The coupling port 75 as exemplified in the drawings is protrudedupwardly from the ceiling plate 73, an integral threaded part 77 of malethreads are formed thereon, a plug 78 is threaded with the threaded part77 as designated by a dotted chain line in the drawings to close theport 75, or a flow conduit, not shown, used to flow to be describedlater may be threaded to couple therebetween. In this case, it is notednaturally that the threaded part 77 may be formed of female threads, andthe port 75 may not always be protruded but be formed in recess, orfurther may be coupled by mere engagement without providing the threadedpart 77.

A lower couping portion 79 is provided at the peripheral side wall 74.In the exemplified example in the drawings, the coupling portion 79 isformed of female threads, and the bottom unit 71 or the couplingcylinder units 72, 72 are detachably coupled thereto as will bedescribed in detail.

Further, the bottom unit 71 also is of an essentially solid,unperforated construction, being formed of a bottom plate 80 and aperipheral side wall 81 as apparent in FIGS. 11 and 12, and a lowercoupling port 82 is provided through the center of the bottom plate 80.In the embodiment exemplified in the drawings, the coupling port 82 isprotruded downwardly similar to the coupling port 75, a couplingthreaded part 83 is formed on the outer periphery thereof, and a plug78' or a flow conduit may be coupled thereto.

Further, a lower stepwise edge 84 is formed on the middle inner surfaceof the side wall 81, the unit 71 is formed elevationally by a mesh plate85 for placing in contact with the edge 84, and an upper couplingportion 86 is formed of male threads on the outer periphery with theupper end of the side wall 81 formed in a small diameter.

The cylinder units 72, 72, . . . used as required are formed in a solid,unperforated, hollow cylindrical shape, a mesh plate 88 for placing isbonded to the lower stepwise edge 87 formed in the middle height in thesame manner as the case of the bottom unit 71, is elevationally formedin the cylinder units 72, an upper coupling portion 89 of male threadsis formed on the upper outer periphery reduced in diameter, and a lowercoupling portion 90 of female threads is formed on the lower innerperiphery of the same diameter as the coupling portion 89.

To employ this, the liver fine pieces to be frozen are placed on themesh plate 85 for placing of the bottom unit 71, and the lower couplingportion 79 of the cover unit 70 is threaded with the upper couplingportion 86 of the bottom unit 71 in FIG. 12.

In this case, it is noted that the coupling portions 79, 86 may not bethreaded, but a mere engagement may be formed. Refrigerant such as gashelium may be introduced into the vessel by coupling a refrigerantsupply conduit, not shown, to the lower coupling port 82, and is thendischarged from the upper coupling port 75, and the liver fine pieces onthe placing mesh plate are instantaneously frozen entirely in contactwith the refrigerant in this case.

In case of FIG. 11, the cover unit 70 is not coupled directly to thebottom unit 71, but a lower coupling portion 90 of the cylinder unit 72is threaded with an upper coupling portion 86, the liver fine pieces arecontained also on the placing mesh plate 72 of the unit 72, and thecoupling portion 90 of the other cylinder unit 72 is threaded with theupper coupling portion 89 of the cylinder unit 72, thereby coupling thetwo cylinder units 72 in double manner to thread the cover unit 70 withthe cylinder unit 72 of the uppermost stage. In this case, four timesthe liver fine pieces of FIG. 12 may be simultaneously frozen.

In this case, the mesh plate 76 prevents the liver fine pieces frombeing discharged from the upper coupling port 75 by the refrigerantinjected from the lower coupling port 82.

When the liver fine pieces are thus frozen completely as describedabove, the plugs 78, 78' are respectively engaged with the upper andlower coupling ports 75, 82. In this state, the liver fine pieces arefilled in a preservation unit such as by liquid nitrogen forpreservation.

When the frozen liver fine pieces thus preserved as described above arefurther to be used, the plugs 78, 78' are removed, the frozen liver finepieces are thawed by predetermined means. Then, flow conduits in theartificial auxiliary liver device are respectively coupled to the upperand lower coupling ports 75, 82, and the auxiliary liver device is thenoperated to pass the patient's blood to the liver pieces and to thenreturn the blood to the patient.

As exemplified in the third embodiment of the freezing vessel accordingto the present invention, the freezing vessel comprises the cover unit70 formed of the ceiling plate 73 and the peripheral side wall 74 insuch a manner that the upper coupling port 75 closed by the mesh plate76, capable of being coupled with the flow conduit and being closed bythe plug 78 is formed through the ceiling plate 73, the cover unit 70formed with the lower coupling portion 79 at the peripheral side wall74, the coupling cylinder unit 72 formed elevationally by the placingmesh plate 88 laterally provided, and provided with the lower couplingportion 79 of the cover unit 70, the detachable upper coupling portion89 and the lower coupling portion 90, and the bottom unit 71 formed ofthe bottom plate 80 and the peripheral side wall 81 in such a mannerthat the flow conduit is provided capable of being coupled to the bottomplate 80 with the lower coupling port 82 capable of being closed by theplug 78', elevationally formed of the placing mesh plate 85 laterallyprovided in the peripheral side wall 81, and provided with the uppercoupling portion 86 detachable from the lower coupling portion 89 or thecover unit 70 or the lower coupling portion 89 of the coupling cylinderunit 72. Therefore, the refrigerant can be rapidly contacted with theliver fine pieces on the placing mesh plate by discharging therefrigerant introduced from the lower coupling port 82 from the uppercoupling port 75, and the liver fine pieces can be desirably frozeninstantaneously.

Further, the quantity of the liver fine pieces to be frozen once can beincreased or decreased by coupling only the cover unit 70 and the bottomunit 71 or by interposing the coupling cylinder units 72 in the desirednumber. Particularly in case of using the liver fine pieces afterthawing as described above, the flow of the blood can be controlledcorresponding to whether the patient is adult or child who used theartificial auxiliary liver device as increased or decreased as describedabove. Further, for preservation or transportation, the vessel can bereadily handled conveniently by the use of the plugs 78, 78'. The frozenliver fine pieces might not be unintentionally discharged from thevessel by arranging the mesh plate 76, and can be used by connecting thevessel to the artificial auxiliary liver device. Consequently, anothervessel for this purpose need not be prepared.

A fourth embodiment of the freezing vessel according to the presentinvention will be described in detail with reference to FIGS. 13 to 16.A housing unit 100 formed in a cylinder and made of synthetic resin suchas Teflon, is formed respectively with an upper coupling port 103 and alower coupling port 104 at the centers of the upper and lower portions101 and 102 therethrough.

In the embodiment exemplified in the drawings, the coupling ports 103and 104 are not only protruded upwardly and downwardly, but couplingthreaded parts 105 and 106 are respectively formed as male threads onthe outer peripheries thereof. Thus, in case that blood is flowed to bedescribed later, a flow conduit is coupled by threading to the couplingports 103, 104 or plugs 107, 107' are engaged as designated byone-dotted chain lines in FIG. 14, and can be closed. In this case, itis noted that the coupling threaded parts 105, 106 are not formed, but amere engagement means may be employed for coupling therebetween, or thethreaded parts 105, 106 may be formed as female threads in the samemanner as the third embodiment as described above.

In the unit 100, two or more mesh plates 108, 108, . . may be laidelevationally, thereby forming containing chambers 109 of predeterminednumber. In FIGS. 13, 14, a containing chamber 109 is formed of only twomesh plates 108, 108. However, in the embodiment in FIG. 15, five meshplates 108, 108, . . . are laterally laid to form four containingchambers 109, 109, . . .

As laterally laying means of the mesh plates 108, 108, as exemplified inthe drawings, the mesh plates 108, 108 are engaged with the supportinggrooves 112 of the supporting projecting strips 111, 111, . . .projected on the inner surface of the peripheral side wall 110 of theunit 100. In this case, since the mesh plate 108 of the uppermost stagedoes not place the liver fine pieces a, a, . . . thereon as will bedescribed later, the mesh plate 108 may employ, as shown in FIG. 16, asmall mesh plate may be bonded fixedly on the upper inner surface of theunit 100 to close the upper coupling port 103.

Further, in this embodiment, exits 113 may be opened at the positioncorresponding to the containing chambers 109, 109, . . . , and a cover114 openably closed on the exit 113 may be provided.

In the embodiment exemplified in the drawings, the cover 114 ispivotally secured by one or more hinges 115. Reference numeral 116designates a sealing member. Thus, in FIG. 14, one cover 114 isprovided, while in FIG. 15, four covers are respectively provided in thechambers 109, 109. In FIG. 15, reference numeral 117 designates a handlefor operating the cover 114, and reference numeral 118 designates anengaging piece projected from the peripheral side wall 110 to hold thehandle 117 in closed state by engaging by rotating the handle 117.

To use the freezing vessel of this embodiment, the cover 114 is opened,the liver fine pieces a, a, . . . to be frozen are introduced from theexit opening 113, which is in a sidewall of the housing unit 100, placedon the mesh plates 108, 108, . . . except the mesh plate of theuppermost stage, the cover 114 is then closed, and a refrigerant supplyconduit, not shown, is coupled to the lower coupling port 104.

Thus, the refrigerant such as gaseous helium is introduced into the unit100, and then discharge from the upper coupling port 103 externally. Inthis case, the liver fine pieces a, a, . . . on the mesh plates 108,108, . . . are instantaneously frozen entirely in contact with therefrigerant.

At this time even in any of the freezing vessels in FIGS. 14 and 15, themesh plate of the uppermost stage serves to perform prevention ofunintentional discharge of the liver fine pieces on the mesh plates 108from the upper coupling port 103 due to the refrigerant injected fromthe lower coupling port 104.

As described above, when the freezing of the liver fine pieces isfinished, the plugs 107, 107' are engaged with the upper and lowercoupling ports 102, 104 as shown in FIG. 14, the liver fine pieces maybe preserved in a preservation unit, for example, with liquid nitrogenin this state, or may be removed, transported or carried.

Further, when the frozen liver fine pieces thus frozen and preserved asdescribed above are to be used, the plugs 107, 107' are removed, thefrozen liver fine pieces are thawed by predetermined means, and a flowconduit of the artificial auxiliary liver device is coupled to the upperand lower coupling ports 103, 104 as described above, thereby operatingthe device. Thus, the patient's blood is passed to the liver finepieces, and can be returned to the patient.

In the fourth embodiment exemplified in the drawings, the flow conduitis capable of being coupled to the upper portion 101 and the lowerportion 102 of the unit 100, the upper coupling port 103 and the lowercoupling port 104 are respectively formed therethrough to close theplugs 107, 107', two or more mesh plates 108, 108', . . . are laterallylaid elevationally in the unit 100, the exit 113 is opened correspondingto the containing chamber 109 thus formed, and the exit opening 113 iscapable of being opened by the cover 114. Therefore, the refrigerantintroduced from the lower coupling port 104 is discharged from the uppercoupling port 103, thereby enabling to contact the refrigerant with theliver fine pieces on the mesh plates. Consequently, the liver finepieces can be instantaneously frozen as desired.

Further, the flow conduit or the plugs 107, 107' are coupled with thecoupling ports 103, 104. Thus, to use the liver fine pieces afterthawing, the vessel may be connected to the artificial auxiliary liverdevice as it is for use. The handling of the vessel is convenient by theuse of the plugs 107, 107' for the preservation or transportation, andthe liver fine pieces might not be unintentionally discharged even bythe mesh plate of the uppermost stage.

What is claimed is:
 1. A freezing vessel for fabricating frozen fineliver pieces for an artificial liver comprising:an essentially solid,unperforated cover unit formed of a ceiling plate and a peripheral sidewall, the ceiling plate including an upper coupling port extendingthrough the ceiling plate and capable of being selectively coupled witha first coolant flow conduit, or closed by a first plug for transportpurposes, the cover unit also including a mesh plate for preventingmovement of the fine liver pieces out of the vessel through the uppercoupling port, and the peripheral side wall being formed with a lowercoupling portion, at least one solid, unperforated hollow couplingcylinder unit including an upper coupling portion selectively detachablefrom or rigidly connectable to the lower coupling portion of said coverunit, and including a lower coupling portion, and an essentially solid,unperforated bottom unit formed of a bottom plate and a peripheral sidewall, the bottom plate including a lower coupling port extending throughthe bottom plate and capable of being selectively coupled with a secondcoolant flow conduit, or closed by a second plug for transport purposes,and the peripheral side wall including an upper coupling portionselectively detachable from or rigidly connectable to the lower couplingportion of an adjacent one of the coupling cylinder units; and at leastone of the coupling cylinder units or the bottom unit including alaterally positioned mesh plate for supporting the fine liver pieces inthe vessel.
 2. The freezing vessel as claimed in claim 1, wherein theupper and lower coupling ports are respectively protruded outwardly fromthe ceiling plate and the bottom plate, the coupling ports arescrew-threaded, and the mesh plate in the cover unit is bonded to aninner surface of the ceiling plate laterally across the upper couplingport.
 3. The freezing vessel as claimed in claim 1, wherein the lowercoupling portion of the cover unit, the coupling portions of eachcoupling cylinder unit and the upper coupling portion of the bottomunit, are formed with respective mating screw threads so that the coverunit, each coupling cylinder unit and the bottom unit can be screwedtogether, and each mesh plate for supporting the fine liver pieces isbonded to a downwardly facing stepwise edge formed at a periphery of aperipheral edge wall inner surface of one of the coupling cylinder unitsor the bottom unit respectively.
 4. A freezing vessel for fabricatingfrozen fine liver pieces for an artificial liver comprising:anessentially solid, unperforated cover unit formed of a ceiling plate anda peripheral side wall, the ceiling plate including an upper couplingport extending through the ceiling plate and being capable of beingselectively coupled with a first coolant flow conduit, or closed by afirst plug for transport purposes, the cover unit also including a meshplate for preventing movement of the fine liver pieces out of the vesselthrough the upper coupling port, and the peripheral side wall beingformed with a lower coupling portion, and an essentially solid,unperforated bottom unit formed of a bottom plate and a peripheral sidewall, the bottom plate including a coupling port extending through thebottom plate and capable of being selectively coupled to a secondcoolant flow conduit, or closed by a second plug for transport purposes,the bottom unit also including a laterally positioned mesh plate forsupporting the fine liver pieces in the vessel, and also including anupper coupling portion selectively detachable from or rigidlyconnectable to the lower coupling portion of the cover unit.
 5. Afreezing vessel for fabricating frozen fine liver pieces for anartificial liver comprising:housing means for receiving the frozen fineliver pieces, an upper coupling port and a lower coupling port on thehousing means, each of the upper and lower coupling parts being adaptedto be selectively connected to a respective coolant flow conduit, orclosed by a respective plug for transport purposes; at least two meshplates laterally positioned in the housing means in vertically spacedrelationship, with at least one of the mesh plates being adapted tosupport the fine liver pieces for contact with a coolant flowing throughthe housing means, an opening in a sidewall of the housing means forpositioning the fine liver pieces in the housing means, and a cover foropening and closing the opening in the sidewall of the housing means. 6.The freezing vessel as claimed in claim 5, wherein one of the meshplates which is in an uppermost position is contacted fixedly with aninner surface of an upper part of the housing means for preventingmovement of the frozen fine liver pieces out of the upper coupling port.7. The freezing vessel as claimed in claim 5, wherein the housing meansis of essentially solid, unperforated construction.